Coherent meson production as a test for neutral weak currents of exotic space-time structure

Abstract

Usually the weak neutral current is assumed to be a vector-axial vector current, but exotic space-time structures such as scalar, pseudoscalar and tensor currents are not excluded by experiment. In this paper we discuss the coherent production of the π 0 and the ϱ 0 in neutrino scattering, as a possibility of distinguishing between VA and SPT. We have calculated the pion production cross sections numerically using the optical model approximation. Pion production is strongly suppressed in the forward direction for SPT but not for VA. In ϱ production the VA cross section is suppressed if CVC holds. Tensor currents can be distinguished from CVC violation. Assuming VA, the absolute pion production rate can be used as a model-independent test for the signs of the chiral coupling constants of the weak neutral quark currents.